1. Field Of The Invention
This invention relates to differential assemblies for use in motor vehicles. More particularly, it relates to differential assemblies having an input drive shaft coupling and two colinear, opposed half axles extending perpendicularly outward from the input drive shaft axis.
2. Description Of The Prior Art
Conventional vehicle differentials generally employ an input pinion gear coupled to the end of an input drive shaft which is rotated by the vehicle engine. In the conventional differential, the input pinion gear drives a crown or ring gear whose rotation axis is perpendicular to the rotation axis of the input pinion gear. The crown or ring gear is rotably mounted coaxially over the inner end of one half axle. One wheel of the vehicle is mounted to the outer end of the half axle. A second wheel and half axle are mounted at the opposite side of the vehicle.
A box-like structure differential housing or carrier referred to as the differential housing is mounted rigidly to the inner side of the crown or ring gear. The inner ends of both half axles extend inward through openings on opposite sides of the carrier, and are rotatably supported there within. Rigidly mounted to the ends of both half axles within the carrier are side bevel gears which face inward. The side gears are similar in appearance to the crown or ring gear, but smaller. Meshing at right angles with the pair of side gears are two opposed pairs of inwardly facing differential pinion gears which are rotatably mounted to the carrier. The axes of the two opposed pairs of differential pinion gears are perpendicular to one another and to the common axis of the half axles.
When a vehicle with a conventional differential as just described travels in a straight line, the crown or ring gear, differential carrier, side gears and attached half axles all rotate at the same angular velocity. In that situation, the differential pinion gears do not rotate around their own axes.
However, when the vehicle turns, the axle half shaft attached to the outward wheel turns faster than the axle half shaft attached to the inboard wheel. The accompanying relative rotational motion of the half shafts with respect to one another is permitted by the rotation of the differential side gears with respect to one another, and with respect to the differential carrier. This imparts a corresponding, opposed rotation couple to each pair of opposed differential pinions about their own axes. The rotation of coaxial differential pinion gears pairs relative to one another permits the two side bevel gears which mesh with the differential pinion gears and which are rigidly connected to the two axle half shafts to rotate with different speeds required for inboard and outboard wheels.